I’ve never been a real plasma user (played around with it sure but never more than a week or something) and have been using GNOME since ~3.10 the whole workflow is just ingrained in my mind and simply works. So I’d be happy to hear how you’re doing on Plasma even if I don’t see myself switching anytime soon.
They absolutely do have “Startup Applications” in gnome not sure what the article is describing but I usually use gnome-tweak which offers a simple interface that shows currently running apps and a list of all apps and easily lets you select them to start at boot
I remember first hearing about 1TB and thinking (who needs that much storage?) wasn’t an IT person then just a regular nerd but am now and it took me a while to ever fill up my first 1TB HDD (steam folder) now I have a 2TB NVME in my desktop and a 4TB NVME in my server (for my Linux ISOs ;))
I feel that. I’ve used Linux before systemd but when I went into the “nitty gritty” by using arch systemd had just been implemented and everything I learned about startup services init etc. was systemd based. When I started my career working in servers they were redhat/CentOS so still systemd and when I switched jobs Debian already had made the switch so (most of) the systems at my new job were also systemd based. Of course I learned the basics of init files and even some rc.d but systemd still makes the most sense to me and like you say it’s “comfy”.